[Why]
    [   41.285804] RIP: 0010:amdgpu_ras_feature_enable+0x15c/0x310 [amdgpu]
    [   41.285945] Code: 48 89 c1 48 c7 c2 b9 f2 88 c1 48 c7 c0 c0 f2 88 c1 49 8b 3c 24 48 0f 44 d0 48 c7 c6 98 33 80 c1 e8 5f 52 75 d9 e9 fa fe ff ff <0f> 0b e9 66 ff ff ff 48 8b 3d 86 8c 0f da ba 00 04 00 00 be c0 0d
    [   41.285946] RSP: 0018:ffffbccdc72efc90 EFLAGS: 00010246
    [   41.285948] RAX: 0000000000000004 RBX: ffff931897406980 RCX: 0000000000000002
    [   41.285949] RDX: 0000000000000dc0 RSI: 0000000000000002 RDI: ffff931500042b00
    [   41.285950] RBP: ffffbccdc72efcc0 R08: 0000000000000002 R09: ffff931885b87000
    [   41.285951] R10: 0000000000ffff10 R11: 0000000000000001 R12: ffff931893e20000
    [   41.285952] R13: 0000000000000001 R14: ffff931885b87000 R15: 0000000000000000
    [   41.285953] FS:  0000000000000000(0000) GS:ffff931c6f200000(0000) knlGS:0000000000000000
    [   41.285954] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [   41.285955] CR2: 000055dd6f532008 CR3: 000000061b010006 CR4: 00000000003706e0
    [   41.285956] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    [   41.285957] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
    [   41.285958] Call Trace:
    [   41.285959]  <TASK>
    [   41.285963]  ? gfx_v11_0_early_init+0x250/0x250 [amdgpu]
    [   41.286117]  gfx_v11_0_late_init+0x8c/0xb0 [amdgpu]
    [   41.286271]  amdgpu_device_ip_late_init+0x8d/0x3c0 [amdgpu]
    [   41.286401]  amdgpu_device_init.cold+0x1677/0x1fda [amdgpu]
    [   41.286616]  ? pci_bus_read_config_word+0x4a/0x70
    [   41.286621]  ? do_pci_enable_device+0xdb/0x110
    [   41.286625]  amdgpu_driver_load_kms+0x1a/0x160 [amdgpu]
    [   41.286762]  amdgpu_pci_probe+0x18d/0x3a0 [amdgpu]
    [   41.286898]  local_pci_probe+0x4b/0x90
    [   41.286901]  work_for_cpu_fn+0x1a/0x30
    [   41.286903]  process_one_work+0x22b/0x3d0
    [   41.286905]  worker_thread+0x223/0x420
    [   41.286907]  ? process_one_work+0x3d0/0x3d0
    [   41.286908]  kthread+0x12a/0x150
    [   41.286911]  ? set_kthread_struct+0x50/0x50
    [   41.286913]  ret_from_fork+0x22/0x30

[How]
    For specific asic, only mem ecc is enabled, sram ecc is not enabled,
    but it still need to send ras enable cmd to gfx block to support
    poison mode, so add check posion mode.
Signed-off-by: Stanley.Yang <Stanley.Yang@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>